Mineral wool product and the method of making it



May 5, 1942. w. M. MacALPlNE MINERAL WOOL ERODUCT AND THE' METHOD OFMAKINGy IT Filed Jan. 25, 195s INVENTOR. Will/'am M. MaC/Hp/'na BYVMXQ./M

ATTORNEY' Patented May 5,

MINERAL WOOL PRODUCT AND THE f METHOD OF MAKING IT william ML Macmpi'ne,Somerville, N. J., assignor to Johns-Manville Corporation, New York, N.I., a corporation of New York vApplication January 25, 1938, Serial No.186,819

. Clailms.` This invention relates to a mineral wool product and themethod of making it. More pai'-` ticularly, the invention relates to theuse of a drying oil binder i a layer of matted mineral wooliibres.

In hardening a drying oil binder in mineral wool products, such as rock,slag, or glass Wool, special difficulties arise. In the rst place, thevery large amount of oil surface, due to the oil forming a thin coatingover the innumerable iibres, promotes exceedingly quick reaction withthe oxygen of the air brought into contactvwith the drying oil at dryingtemperatures.- In the second place, the thermal insulating effectivenesso a thick layer of mineral'wool tends to preserve within the layer theheat evolved in the reaction of the drying oil with the air. As aresult, it is dilcult to set the drying oil at a desirably hightemperature and rate and, at the same time, avoid burning or badlyscorching the oil, dueto the rise in temperature above that at which thesetting is initiated. For instance, the setting of the drying oil binderat an initial temperature of about 400 to 600 F. ordinarily would leadto serious overheating of the drying oil binder, because of the heatevolved during the setting of the binder.

It is an object of the present invention to overv come the dicultiesencountered in the use of drying oil binders in mineral `wool products.Another object is to provide a mineral wool felt of improved propertiesand an economical method of producing it. Other objects and advantagesreactions are initiated, the large excess of air will appear from thefollowing detailed description.

A preferred embodiment oi.' the `invention will be described inconnection with the attached drawing showing diagrammatlcally a sideview oi' equipment for effecting the setting of the binder. Otherequipment used is conventional and, therefore, not illustrated.

In general, the method is as follows: There is formed a layer or felt ofmatted-mineral wool libres including the drying oil binder compositiondistributed over the bres. 'I'he layer` of iibres and binder is thensubjected to treatment p to harden (set) the binder under conditions socarefully controlled that the binder may be hardcned at a suillcientlyelevated temperature to produce the best results while there isprevented additional riseI of the temperature to such point as toproduce substantial scorching of the binder. ,The desired results areobtained by forcing through the layer a very large excess of hot air.The hot air initiates and promotes the exo- CAB Cal

thermic reactions of setting, such as oxidation and/or polymerization.Once the reaction or maintains the binder composition at the` desiredtemperature and carries away heat which is developed by the setting andwhich, otherwise, would cause scorching. 'I'he setting occurs in arelatively short period of time. l

The invention will be illustrated more speciflcally bythe followingdetailed example.

There is provided, first of all, a molten silicate lcomposition suitablefor use in the manufacture of mineral wool. This molten composition isshredded, as by being caused to fall in the form of avery thin streaminto a steam' blast including the selected drying oil binder compositiondispersed in the blast.

r There is thus produced an air suspension of fibres coated with thebinder composition. The bres and adheriner binder are then collectedinto a layer on a suitable felting member. This co1- lection may be made(l) on the moving conveyer constituting the floor of a conventional rockwool blow chamber or, preferably, (2) under the influence of suctionapplied behind as'creen wire or like ielting member. In any case, thefibres are collected into a layer that is relatively thick, say 1/4 inchto e inches or so in thickness.

The felt or layer o! matted fibres thus formed` is then subjected totreatment to set the binder composition therein. Hot air in large excessis passed through the felt. For instance, the felt l is confined betweenscreen or other air-permeable members 2 and 3, disposed on oppositefaces of the felt and, suitably, pressed thereagainst by pressureapplied between theskeleton supports i and 5 whereby the thickness ofthe fibrous layer is established during the setting operation. Preheatedhot air is supplied through the line 6, and is passed through theportion of the felt to the right in the drawing, the ail` being mixedwith a predetermined amount of additional hot air in the blower 1, andreturned through line 8 to the drier proper and then passed'through theportion of the felt at the ting of the binder and at no time is so highas lto produce substantial scorching of the binder,

by which term is meant thermal decomposition with objectionable loss ofstrength, toughness, or

`resiliency of the binder.

Because these temperatures are dangerously near the temperature ofscorching ofthe binder composition, it is important that some means beprovided for rapid cooling to offset lthe heat developed by thereactions accompanying the setting. For this purpose, there is used anamount of air largely in excess of that required lto oxidize the dryingoil binder. .Advantageously,

the amount of air admitted through line 6 diluted ment, is such thatthere is no large rise in temperature of the air passing through thefelt. For

instance, there have been used linear vvelocities of air through `thefelt, in the direction from face to back thereof, of the order of 30 to100 feet a `minute. Air at such a velocity effects the desired coolingand, on the other hand, does'not cause blowing oriibres from the felt or.roughening of it to an objectionable extent. In general, thetemperature used and the amount of air blown 1 through should be such asto give a'quick oxida ,tion and/or polymerization of the drying oil, lywith the elimination of compounds of objection- Vable odor. Thus,.there are used to advantage a total setting time of the order of 1 to 10minutes. Due to the shortness of this time period, the pos- `sibility ofundesired side reactions occurring at the prevailing high temperaturesis minimized.

There maybe used, for instance, about 1,000

to 4;000 cubic feet of air (measured at standard pressure andtemperature conditions, namely, 760

, `somewhat by leaks around the edges of the equipkerosene has beenseparated and which remains as stock for the manufacturing oflubricating oil.

In general, the hardening and the plasticizing agent selected should befreely soluble in the drying oil used, water-repellent, practicallynonvolatile under all conditions of use, and resistant to decompositionat all temperatures to which the mineral wool is exposed during themanufacture of the product of the present invention.

The binder composition, suitably, includes a conventional drier for thedrying oil that is oil` soluble, as, for instance, lead, manganese,cobalt, or iron naphthenates'or resinates. The proportion of drier maybe'varied within limits but is preferably about 0.3 to 1 part to 100parts of the drying oil. Preferably, also, the drier as used is amixture of two or more of the individual driers above. u

Following are illustrative formulae for the binder composition, theproportions being given as parts by weight:

. Example Il Drying oil l 80 plasticizer 30 Driers 0.5

Example II Drying ou a0 Gusonite a Plasticizer 4 Driers 0.3

mm; of mercury and c'C.) for each pound of drying oil in the binder.

There may be'used various drying oils, as, for

` example, linseed, perilla, oiticica, and hempseed. However, perillaoil, either alone or mixed with moderate proportions of one of the otherdrying 1 oils, has been found to give outstanding results.

In making a mineral wool product that is to be mixed with a hardeningagent. On the other "hand, a plasticizing agent may be used to make asofter or more flexible felt. -As a matter of relatively rigid andresilient, such as a felt for lining automobile bodies or the metalcases of electric refrigerators, the drying oil is preferably economy,there may be used, in many cases, a

` hardening and a softening agent; in this way the amount of the ratherexpensive drying oil maybe decreased by substitution of cheapermaterials, without development of either i like.

Plasticizing agents that may be used are a semidrying oil, such as fishoil or soya bean oil, 1 asphaltic fluxes characterized-by relatively lowtemperature of softening and high penetration,

and/ or a petroleum oil that is miscible in all proportions with thedrying oil, is a liquid' at normal temperatures, and is practicallynonvolatile at 500 F, Such a petroleum plasticizer is the fraction ofPennsylvania oil from which The proportion of drying oil is usuallyabout half or more of the total composition, the other ingredients beingvaried to give the hardness, rate of oxidation, or waterproofnessdesired.

While the drying oil itself is somewhat waterrepellerlt, greaterresistance to wetting by water is imparted by the hardening orplasticizng agent used.

Mineral w-ool products including a small pro portion of the bindercompositions recited above, say, in the proportions of l to 6 partsbinder to parts total weight of the products, not only permit setting ofthe binder without overheating but also are not readily combustible inthe finished form. In fact, products so made do' not carry a flame anddo not continue to smoulder after being exposed for a short time to theflame of a gas burner.

On the other hand, the products are coherent,v somewhat sprin'gy andresilient, and of very low density, the density varying somewhat withthe amount of pressure, if any, applied 'to the layer of matted bresduring the step of setting the binder.

When the drying oil is introduced into the,

blast of steam before the steam strikes the molten mineralwoolcomposition and berizes it, a particular effectof the drying oil isnoted. The application of the drying oil in this manner, for

some unexplained reason, promotes the formation of longer libres, lessdust, and better matting or felting than is the case if other binder` isused or if the drying oil is applied subsequent to the blast becomesdistributed over a large part of the 1 total surface of the mineral woolfibres.` However, the term "coating or coated aslapplied i to the bindercomposition is intended to include a flhn extendingeither continuouslyory discontinuously over the exterior portions of the bres.

aaeaeeo required to set the drying oil, the temperature within the saidlayer being maintained during the passage oi the air at a maximumtemperature above 500 F. and below the temperature of substantialscorchingoi the drying oil. l

2. The method of making a mineral wool product which comprises formingathick layer, lncluding matted mineral wool 4fibres and a drying oilbinder distributed thereover,` and passing a large excess of warm airthrough the said layer. while maintaining thereina temperature of theorder of 500 F. i

3. The method of making a mineral wool product which comprises forming athick layer, including matted mineral wool libres and a drying oilbinder distributed thereover, and passing preheated air through the saidlayer at an average linear velocity ofthe ordex` of 30 to 100 feet perminute, the maximum temperature within the layer being maintained abovev500 F. and below the temperature of substantial scorching of the dryingoil binder.

fi. 'Ihe method of making a mineral wool product which comprises forminga thick` layer, in;- cluding matted mineral wool bres and a drying oilbinder distributed thereover, and passingfa large excess of preheatedair through the layer,

the said layer being maintained during the treatment with air at amaximum temperature of the mately the maximum vtemperature beingcondrying oil substantially 'completely but not in excess of 20minutes'.

5. An article of manufacture comprising a layer of matted mineral woolfibres and a binder distributed thereover, the binder consisting chieflyof perilla oil in set condition and being ln the proportion of 1 to 6parts to 100 parts total Weight of the article.

6. An article of manufacture comprising a layer I of matted mineral woolfibres and a binder distributed thereover, the binder consisting chieflyof oiticica oil in set condition and being in the proportion of 1 to 6parts to 100 parts total weight of the article.

7. An article of manufacture comprising a layer of-y mineral wool fibresandabinder distributed throughout said layer. the binder comprisingperilla oil in set condition and la. hardening agent, the proportion ofthe binder composition being 1 to 6 parts to 100 parts total weight ofthe article.

8. An article of manufacture -comprising a layer of mineral woolfibres'and a binder distributed throughout said layer, the bindercomprising perilla oil in set condition and a plasticizing agent, theproportion of the binder composition being 1 to 6 parts to 100 partstotal weight of the article;

9. 'I'he method of making a mineral wool product comprising forming afelted layerl including mineral wool fibres and a binder-,composedprincipauy of perilla oil distributedl thereover, and passing a largeexcess of warm air through said layer while maintaining therein atemperature torapidly harden said oil.

10. The method of making a mineral Wool product which comprises forminga thick layer, including felted mineral Wool fibres and a drying oilbinder distributed thereon, and passing air through said layer in anamount greatly in excess of that required to set the drying oil, whilemainorder of 600 F.' and the treatment at approxitinued for a period oftime adequate to set the` taining in said layer a temperature of theorder of 400 to 600 F.

WILLIAM M. MAcALPINE.

